This application claims the priority of German Patent Document 198 57 392.8 filed Dec. 12, 1998, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a sealing arrangement for a shaft guided through an opening, especially a wall opening in a motor vehicle. The shaft is mounted rotatably relative to the opening and has a profiled surface section with an elastic cuff mounted at the opening and enclosing the shaft. The cuff abuts the shaft through a supporting ring.
A seal for a shaft guided through a wall opening is known from DE 29 32 317 C2. The seal has a disk-shaped sealing element connected non-rotatably with the shaft. The disk-shaped sealing element is accommodated in a double-walled receiving chamber located at the wall opening. The sealing element has sliding and/or sealing surfaces located endwise that are in intimate contact with the interior of the receiving chamber. The size of the sealing element is chosen so that the sealing element and the wall opening overlap completely in every angular position of the shaft. The shaft can be mounted eccentrically with respect to the wall opening.
A sealing element for passing the steering column of a motor vehicle through a wall opening is known from utility model DE 94 05 633 U1. This element has a sealing body secured at the wall opening into which a bushing is inserted by which the steering column is guided.
A covering unit for a wall opening in a motor vehicle is provided in Offenlegungsschrift DE 42 21 669 A1 through which a steering column is guided. The covering unit consists primarily of a first cover plate into which a sealing and guide bushing for the steering column is integrated and which is mounted on the wall opening from one side such that the guide bushing passes through the wall opening. A matching plate is placed on the wall opening from the other side and latched to the guide bushing.
A sealing arrangement for a steering column of a motor vehicle guided through a wall opening is known from Offenlegungsschrift DE 43 44 385 A1. The arrangement comprises a sealing lip surrounding the wall opening and a holding part holding the arrangement. The holding part as well as the sealing lip made in the form of a hollow bead are mounted on a jacket tube of the steering column.
The goal of the present invention is to provide a sealing arrangement that permits especially good sealing of a wall opening and that can be used with shafts having a surface portion of any desired profile.
This goal is achieved according to the present invention by virtue of the fact that an elastic sealing jacket is associated internally with a supporting ring, by means of which the jacket is mounted nonrotatably on a shaft. The supporting ring has an external cylindrical sliding surface on which an elastic cuff is mounted. The sealing jacket is flexible and elastically deformable so that it adapts to the profile of the surface portion of the shaft and surrounds the shaft in a sealing fashion. The supporting ring presses the sealing jacket in a self-locking manner against the shaft and provides an external surface on which the cuff can slide when the shaft rotates. For this purpose, the supporting ring has a slight dimensional tolerance relative to roundness and good sliding properties at its outer surface. With the proposed arrangement, both a good seal at the opening traversed by the shaft and compensation of dimensional tolerances of the shaft can be achieved. With the aid of the proposed sealing arrangement, shafts that are out-of-round (not precisely round) can be sealed as well.
In the embodiment of the present invention, the supporting ring has (1) a clamping ring section that can be spread apart elastically at least areawise, with which section the elastic sealing jacket is associated; and (2) a sliding ring section having a cylindrical sliding surface that can be connected releasably with the clamping ring section. The clamping ring section can be compressed elastically in its elastically spreadable area so that the sliding ring section can be pushed onto the clamping ring section and tensioned radially. The sealing jacket can be pressed against the shaft by a section that corresponds to the elastically spreadable area of the clamping ring section.
In another embodiment of the present invention, the clamping ring section, especially in its elastically spreadable area, can be provided with one or more lengthwise slots. As a result, an especially high degree of reversible deformation of the clamping ring section can be achieved.
In another embodiment of the present invention, the sealing jacket is permanently connected to the clamping ring section and has an internal constriction in a section that corresponds with the elastically spreadable area of the clamping ring section. The sealing jacket, preferably made of an elastomeric plastic, is connected materialwise (especially by gluing, welding, or injection molding) with the clamping ring section. The constriction is produced by a preferably spherical or conically tapered internal surface. Preferably, the wall thickness of the sealing jacket is greater in this area. When the unit composed of the sealing jacket and the clamping ring section is pushed onto the shaft, both elements are stretched elastically so that they automatically clamp on the shaft.
In another embodiment of the present invention, the clamping ring section, especially in its elastically spreadable area, has a conical outer contour and the sliding ring section, especially in an area that corresponds to the elastically spreadable area of the clamping ring section, has a conical internal contour that matches the outside contour of the clamping ring section. This produces a self-locking frictional clamping connection along a diagonal conical surface that permits equalizing the tolerance depending on the axial length of the clamping ring and sliding ring sections that are pushed on.
In another embodiment of the present invention, latching elements that fit into one another, especially matching teeth, are located between the sliding ring section and the clamping ring section. This produces a simple, reliable latching connection.
In another embodiment of the present invention, the sliding ring section has an internal thread and the clamping ring section has a matching external thread. As a result, an especially reliable screw connection is produced. The sections of the thread produce latching elements in the axial direction.
In another embodiment of the present invention, the clamping ring section has a rigid annular flange. The radially projecting flange serves to stiffen the clamping ring section and acts as a stop surface for the sliding ring section that is slid on.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.